Atletico Madrid goalkeeper Thibaut Courtois will be able to play against Chelsea in the Champions League semi-finals without the La Liga club having to pay them a penalty fee, an Atletico director said on Friday (local time).

Belgium international Courtois has been on loan at the La Liga side from parent club Chelsea since 2011 and the two clubs were paired with each other in the last four of Europe's elite club competition in Friday's draw.

Atletico president Enrique Cerezo said after Atletico qualified there was a clause in the loan deal which meant the club would have to pay "a lot of money" to Chelsea if Courtois were to play against the Londoners.

Spanish media reported it would have been 3 million euros ($4.2 million) for each game.

However, Atletico director Clemente Villaverde and European soccer's governing body UEFA both said on Friday such a clause would breach competition rules.

"Courtois can play whatever happens," Villaverde said in an interview with Canal Plus after the draw.

"There is a UEFA regulation which prohibits any agreement between clubs that prevents a player from participating freely in the competition," he added.

"The regulation would have been breached if the player had not been allowed the freedom to participate."

UEFA published a statement that said if Chelsea enforced the penalty clause for the two-legged semi-final tie they would be sanctioned.

"Both the UEFA Champions League and the UEFA Disciplinary Regulations contain clear provisions which strictly forbid any club to exert, or attempt to exert, any influence whatsoever over the players that another club may (or may not) field in a match," the statement said.

"It follows that any provision in a private contract between clubs which might function in such a way as to influence who a club fields in a match is null, void and unenforceable so far as UEFA is concerned."

Courtois has been a key figure in Atletico's recent success and turned in another brilliant performance in Wednesday's 1-0 victory against Barcelona which put them through to their first semi-final in 40 years.

Chelsea chief executive Ron Gourlay confirmed on Friday the club would allow Courtois to play but did not directly address the issue of the penalty fee.

"The loan was arranged back at the start of the season. He can play against Chelsea, that's never in doubt," Gourlay said on Sky Sports.

"Regarding the UEFA statement we'll evaluate that in due course," he added.

"As far as we are concerned we will comply with loan rules. He can play in both ties against Chelsea if selected. That is fact."